This is an AIDS Clinical Trial Group (ACTG) ongoing study designed to evaluate the potential late effects of therapies received in HIV- infected and HIV-uninfected infants, children and adolescents, currently or previously enrolled in pediatric ACTG protocols. The major aim is to longitudinally follow patients who have participated in perinatal and pediatric ACTG clinical trials in order to monitor late consequences of therapy, including long-term survival and quality of life.